Chapter 8 - Noise and OSHA's Hearing Conservation Program Flashcards

1
Q

OSHA Hearing Conservation Program required when

A

an employee’s noise exposure equals or exceeds an 8-hr time-weighted average sound level of 85 dB on the A-scale (slow response) or equivalently a dose of 50%

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2
Q

Do you need to implement a hearing conservation program if sound level exceeds 85 dB, but this noise exposure is attenuated by devices such as earplugs, muffs, or bands?

A

Yes!

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3
Q

Monitoring program

A

required when information indicates that any employee’s noise exposure may equal or exceed an 8-hr. TWA

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4
Q

Monitoring sampling stragety

A

Designed to identify employees to be included in program
Continuous, intermittent, and impulsive sound levels from 80-139 dB shall be integrated into measurements
Monitoring shall be repeated whenever a change in production, process, equipment, or control occurs

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5
Q

Type 1 sound level meter

A

Used for precision measurements in the field

Accuracy of +/- 1 dB

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6
Q

Type 2 sound level meter

A

Used for general purpose measurement in the field
Accuracy of +/- 2 dB
minimum measuring device allowed for determining an employee’s noise level exposure under the OSGA Hearing Conservation Standard

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7
Q

Sound level meters used to

A

spot check employee exposures
identify potential noise sources needing further evaluation
Assist in the feasibility of engineering controls

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8
Q

Octave band analyzer

A

Sound level meter that measures noise levels at various frequencies
useful to analyze sources of noise on the basis of frequencies, determining specific noise attenuation devices to recommend
divide noise into frequency components
provide reading for 31.5 Hz, 63 125, 250, 500, 1000, 2000, 4000, 8000, 16000

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9
Q

Noise dosimeter

A

sound level meter worn by the employee for a period time- computes dose and overall noise exposure

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10
Q

Employee notification

A

required if employee is exposed at or above 8 hr TWA of 85 dbA
affected employee or representative must have opportunity to observe noise measurements conducted

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11
Q

Audiometric testing

A

must be performed on any employee in the program

must be conducted by an audiologist, otolaryngologist or a certified technician

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12
Q

Baseline audiogram

A

within 6 months of first exposure greater than 85 dBA

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13
Q

audiometric testing

A

Baseline shall be preceded by 14h without exposure
annually after baseline
Must be pure tone, air conduction tests in the 200, 1000, 2000, 3000, 4000, 6000 Hz

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14
Q

Standard Threshold shift

A

change in hearing threshold relative to that baseline audiogram of an average of 10dB or more at 2000, 3000, or 4000Hz in either ear
This is a recordable injury
Must make allowance for contribution of aging

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15
Q

Hearing Conservation Program Training

A

Enrolled employees must train within 30 days of exposure
Topics include:
effects of noise on hearing,
purpose of hearing protectors (advantages/disadvantages of various types),
selection, fit and use and care of hearing protectors
purpose of audiometric testing

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16
Q

Hearing Conservation Program Record Keeping

A

Audiometric test record -
Name and job classification of employee
date of audiogram
examiner’s name
date of the last acoustic calibration
employee’s most recent noise exposure assessment
Noise exposure measurements required every 2 years

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17
Q

Noise

A

Unwanted sound
Harmful to humans
Can create a hearing loss if uncontrolled

18
Q

Continuous Noise

A

sound that has unbroken sound waves of one or more different frequencies

19
Q

intermittent noise

A

sound that has broken sound waves or is non-continuous

20
Q

Sound

A

Oscillations in pressure above and below the ambient atmospheric pressure, generated by a vibrating surface or turbulent fluid flow, causing high and low pressure areas to be formed, which propagate away from the source

Mechanical vibrations transmitted through an elastic medium.

A sensation is produced by stimulation of organs of hearing by vibration

21
Q

Frequency

A

number of complete cycles of a sound wave in 1 second
measured in Hz
normal range of hearing for human is 20-20000 Hz

22
Q

Period

A

time required for one cycle

Reciprocal of frequency

23
Q

Speed or velocity of sound

A
wavelength * frequency
depends upon the medium density and compressibility
speed of sound in air = 332 m/s
speed of sound in water = 1500 m/s
speed of sound in steel = 6100 m/s
24
Q

Wavelength

A

distance traveled during one pressure cycle

25
Q

Outer ear

A

designed to collect sound vibrations
composed of the pinna (ear lobe), which gathers sound waves and directs them toward the external auditory canal and onto the tympanic membrane

26
Q

Middle ear

A

Transmits mechanical vibrations from the air into vibrations in fluid
Ossicle
Eustachian tube which equalizes pressure between middle and outer ear
Oval and round window

27
Q

Inner ear

A

Changes mechanical waves in a liquid to chemical impulses sent to the brain
Cochlea
Organ of corti - essential receptor and organ for hearing and contains the hair cells

28
Q

Five types of hearing loss

A
Conductive
Sensorineural
Mixed
CNS
Psychogenic
29
Q

Conductive hearing loss

A

occurs in the outer and middle ear
loss of “loudness”
build up of wax, physical obstruction of eustachian tube or perforation of the tympanic membrane

30
Q

Sensorineural

A

Occurs in the inner ear, hair cells of organ of corti are damaged- mostly irreversible
Damage due to hazardous or excessive noise exposure

31
Q

Mixed

A

conductive and sensorineural damage

32
Q

CNS

A

hearing loss related to CNS occurs between inner ear and brain and many cuases are not related to noise exposure

33
Q

Psychogenic

A

Occurs in the mind, may be result of some type of emotional trauma

34
Q

Major cause of hearing loss

A

Obstruction and disease
acoustic trauma
prebycusis (age-related) / sociocusis (continuous noise exposure not related to occupation)
noise induced

35
Q

OSHA permissibile noise exposures

A
8 hour - 90 dBA
6 hour - 92 dBA
4 hour - 95 dBA
3 hour - 97 dBA
2 hour - 100 dBA
1.5 hours - 102 dBA
1 hour - 105 dBA
0.5 - 110 dBA
0.25 - 115 dBA
36
Q

Entities of Noise

A

sound power, sound intensity, and sound pressure

Power is constant . Intensity decreases with increase in distance according to inverse square law

37
Q

Sound power

A

expressed in terms of its sound power level (Lw or PWL)

38
Q

Sound Pressure

A

Amplitude of sound pressure (Lp) disturbance can be related to the displacement amplitude of the vibrating sound source
Pressure expressed as force per unit area (Pa or one Newton/square meter)

39
Q

Sound Pressure reference level

A

0.00002 N/ square meter

40
Q

Sound Intensity (LI)

A

Similar to pressure level, except that intensity is a vector quantity having both magnitude and directions

41
Q

Acoustic power reference

A

10 ^-12 W

42
Q

Sabin

A

Equal to square footage of surface times the noise reduction coefficient